This invention relates to the preparation of 2-methylene-1,3-propanediamide. More particularly, it relates to a process for preparing this monomer by a .beta.-elimination reaction conducted in the presence of an inert, aprotic organic solvent.
U.S. Pat. No. 2,466,395, issued to J. B. Dickey, discloses the use of 2-methylene-1,3-propanediamide or, more commonly, methylene malonamide, as a comonomer for preparing copolymers useful in preparing films and filaments. The process for preparing this monomer, disclosed therein, is said to comprise a sulfuric acid or hydrogen peroxide hydrolysis of 2-methylenepropanedinitrile, i.e., ##STR3##
This preparative method has certain inherent disadvantages. One disadvantage is that 2-methylene-1,3-propanediamide tends to be unstable in the presence of such reagents as sulfuric acid and hydrogen peroxide, the monomer tending to undergo polymerization or other degradative reactions in the presence of such reagents. Thus, the reaction conditions suggested by U.S. Pat. No. 2,466,395 for preparing this monomer are generally unfavorable in terms of obtaining the desired product and especially in terms of obtaining a high yield of the desired product.
Another disadvantage of the process disclosed in U.S. Pat. No. 2,466,395 is that 2-methylenepropanedinitrile is highly toxic and, as such, is an undesirable intermediate.
The present invention avoids the aforementioned problems and disadvantages by providing a novel process for preparing 2-methylene-1,3-propanediamide which avoids the use of 2-methylenepropanedinitrile and the use of reagents which tend to degrade the product monomer and which is capable of providing the desired product in repeatedly good yield and purity.
It is thus an object of the present invention to provide a process for preparing 2-methylene-1,3-propanediamide.
It is another object of the present invention to provide a process for preparing 2-methylene-1,3-propanediamide with minimal concurrent derivatization or polymerization of the product monomer.
Other objects of this invention will in part be obvious and will in part appear hereinafter.